Description of several materials frequently used in valve stems

During the opening and closing of the valve, the valve stem is subjected to tensile, compressive and torsional forces and is in direct contact with the medium, and there is relative frictional movement between the valve and the packing. Therefore, the valve stem material must ensure sufficient temperature at the specified temperature. Strength and impact toughness, certain corrosion resistance and scratch resistance, and good processability.

Commonly used stem materials are as follows.

First, carbon steel

    For water and steam media with low pressure and medium temperature not exceeding 300 °C, A5 ordinary carbon steel is generally used.

    For water and steam medium with medium pressure and medium temperature not exceeding 450 °C, 35 high quality carbon steel is generally used.

Second, alloy steel

    For medium and high pressure, when the medium temperature does not exceed 450 ° C water, steam, petroleum and other media, 40Cr (chromium steel) is generally used.

    38CrMoALA nitrided steel can be used for mediums such as water and steam with high pressure and medium temperature not exceeding 540 °C.

    For high pressure, medium temperature does not exceed 570 ° C steam medium, generally choose 25Cr2MoVA chromium molybdenum vanadium steel.

Third, stainless acid resistant steel

    Non-corrosive medium and weak corrosive medium for medium and high pressure, medium temperature not exceeding 450 °C, 1Cr13, 2Cr13, 3Cr13 chromium stainless steel can be selected.

    For corrosive media, stainless steel and acid corrosion resistant steel such as Cr17Ni2, 1Cr18Ni9Ti, Cr18Ni12Mo2Ti, Cr18Ni12Mo3Ti and PH15-7Mo can be used.

Fourth, heat-resistant steel

    For high temperature valves with a medium temperature not exceeding 600 °C, Cr10Si2Mo martensitic heat-resistant steel and 4Cr14Ni14W2Mo austenitic heat-resistant steel may be used.